I am a self-trained amateur and shoot product photography for my clothing company. My typical set-up is 2 500-watt continuous softboxes, lighting a product from above with each light just to the left and right of the camera.
I usually add contrast in post, but would like to modify my light set-up to provide a little more contrast and shadowing (under the collar area of the shirt, for example) while still lighting the shirt evenly.
My thought was a different type of light source or perhaps a honeycomb-style grid to make the light a little 'harder.'
An example photo of on of MY images can be seen here (contrast added in post): http://www.ratioclothing.com/images/product/large/72_2_.jpg
An similar style with better contrast can be seen here: http://www.ratioclothing.com/images/product/medium/1_2_.jpg
I can tell the second image uses light that is a little more "directional", so a lighting placement change is needed as well, I'd be curious to hear those thoughts as well.